In recent years, there has been a pronounced tendency that such a gas-insulated switchgear, the entirety of which is significantly reduced in size by accommodating electric devices such as a current carrying conductor and a circuit breaker in a tank sealing sulfur hexafluoride (SF6) gas with high insulation and interruption performances therein, is a mainstream technology of switchgears for electric power in response to an increase in demand for electric power and requirements for a small scale and high reliability of electric power equipment.
The most important component of the gas-insulated switchgear is a gas circuit breaker, and the gas circuit breaker has a structure in which the circuit breaker is supported in a sealing tank with SF6 gas sealed therein via an insulating support.
The aforementioned circuit breaker is required to satisfy the duty of interrupting various currents as well as an ordinary load current, and the performances thereof are significantly affected by opening speeds of a moving arcing contact installed at a moving electrode of the circuit breaker and a fixed arcing contact installed at a fixed-side conductor.
In order to manage the opening speeds of the moving arcing contact and the fixed arcing contact, a managing method of performing assembly so as to set the moving amount of the moving arcing contact until the moving arcing contact and the fixed arcing contact open from the closing position (hereinafter, referred to as a wiped length) within a prescribed value is employed.
However, the aforementioned management method requires precise dimension management of the respective components and a mechanism for adjusting a position of the arcing contact after the assembly, and there is a problem that cost increases for fabrication of the components and the adjustment operation.
In a case of a puffer-type circuit breaker, remaining capacity in a puffer chamber at an opening position significantly affects a pressure rising property in the puffer chamber in the process of the opening operation. Therefore, it is necessary to manage the remained displacement in the puffer chamber at the opening position (hereinafter, referred to as an opened position clearance) at the same time.
For example, the current switchgear disclosed in PTL 1 is designed to perform the assembly such that the wipe and the clearance between arcing contacts are always within predetermined assembly tolerance by adjusting the wipe and the clearance between arcing contacts regardless of the length of a container in an axial direction.